JPH02265201A - Chip component - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a 5A chip component, which is a type of electronic circuit component that contributes to the reduction in weight, thickness, and size of electronic equipment.

2. Description of the Related Art Conventionally, this type of chip component has had a structure as shown in FIG. FIG. 4 shows a cross-sectional view of a square plate type chip resistor as a conventional example, where 1 is a glass wave receiver, a 27D alumina insulating substrate, and 3 is a resistor.

4 is a silver thread electrode, 6' is a nickel electrode, and 6 is a solder or tin film deposited by the five-metal method.
-26458 official uniform, Utility Model Publication No. 65-21282,
Utility Publication No. 55-21283, Special Publication No. 68-1084
Related techniques are also described in Publication No. 3 and Japanese Utility Model Application No. 192401/1983.

Problems to be Solved by the Invention In such a conventional configuration, the poured part in Fig. 4 is tin, the pattern 6 is a plating film, and the surface is shown in the cross-sectional view of the outermost layer electrode in Fig. 6. It has a rough surface that indicates a lady.
The surface area is extremely large. For this reason, these films tend to absorb and absorb foreign substances, and when stored for a long period of time, the electrode surface undergoes chemical changes such as oxidation, which can cause soldering defects when soldering to a printed circuit board. The problem was that the possibility was high.

The present invention solves these problems.

The purpose of this is to reduce the surface area of the electrode part of a chip component and to make it smoother, thereby improving solder wettability and making it easier to solder for long-term storage.

Means for Solving the Problem In order to solve this problem, in the present invention I/i, a low-grade gold 4-plated film is used as the outermost electrode film of the pentode portion.

The base material of the low melting point metal plating in the northernmost part has a higher melting point than this low melting point metal plating film, and is also composed of a material that has good affinity with this low melting point metal plating film, and is The structure is heat-treated at a temperature higher than the melting point of the electrode material, and the outermost layer of the polarized part is coated with re-melting fusion@Kan, and the surface roughness is 0 to 0.6 μm. It is something that you have.

Function: According to this configuration, the width of the electrode film surface of the outermost layer of the turtle shell is small, so the surface area is small, and the surface area is extremely small compared to the state where the plating film of the conventional chip component is intact. Moreover, since the surface is smooth, adhesion of foreign matter and adsorption of gas during storage are extremely reduced, leading to improved solder wettability and reliability of soldering.

Embodiment One embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view of a square plate-shaped chip resistor according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line A--B in FIG. 1. In these FIGS. 1 and 2, the same parts as in the conventional column are given the same numbers, and explanations thereof will be omitted.

In Figures 1 and 2, 7 is a solder or tin film, and after the solder or tin film is deposited on nickel by electroplating, it is heat-treated at a temperature higher than the melting temperature of the solder or tin. It is a metal film that has been subjected to a smoothing treatment on one surface, and its surface roughness is extremely small.

As described above, the chip resistor of the present invention is different from conventional examples in that a low-melting point gold plating film is used for the outermost electrode film of the electrode part, and heat treatment is performed at a temperature higher than the melting point of the electrical filling material. The outermost layer of the electrode part has a structure in which it is covered with a remelted metal film, and its surface roughness is reduced.

Here, the lower pond of the gold 4 metal plate (here Nickel Han 5) to the low 1 is the metal plate to this low 7, which is higher than the metal plate,
It is also necessary that the material is made of a high-A gold material that has an affinity for this low-Ma gold.

Next, solder or tin film γ, which is a metal model,
An example of a specific production/method will be explained. Now, on the alumina-based substrate 1 equipped with the silver thread electrode film 4, a conductive glaze of 20 μm as the resistor 3, a 6 μm of nickel powder 5 as the outermost layer film, and tin:lead=eo:4o (melting point is approx. A 12 μm thick electroplated solder pattern (183° C.) was prepared, which was immersed in rosin-based flux and then heat-treated at 220° C.SO for seconds in a heating furnace. As a result, a solder (still tin) film 7 made of a metal film could be formed on the outermost layer of the polarized portion.

FIG. 3 shows a cross-sectional state of the surface of the outermost layer of the polarized portion of the chip resistor thus obtained. FIG. 3 shows the cross section of the electrode surface after heat treatment, measured using a precision roughness meter.

Too bad conventionally! 11 No. 5: The same conditions apply to the figure (however,
The coating surface of a chip resistor made with mixed air plating (X:d without heat treatment) was also measured with a thickness meter.

Comparing the surface texture of the t-ball in Figure 31 and Figure 5,
The surface of the conventional product, which is the youngest processed product, is a flat surface with unevenness.
It can be seen that the surface of the product of the present invention, whose surface was smoothed by heat treatment, is smooth because the soldered plating pattern is melted, and the surface area is reduced accordingly.

Here, in the above real blood example, the outermost layer is a sample of @
We have explained the case where electroplated film is used as a point metal plating model, but it is also possible to create a low melting point metal plating with chemical plating in that it can obtain a plating with a uniform thickness. be.

Further, the constituent materials of the electrode parts in the above embodiments are not particularly limited to silver, nickel, solder, or tin.

Here, the following tests were conducted to confirm the solder wettability and long-term storage stability of the above examples.

[article]

・Real blood left under accelerated humidity (60″0.95″XRH).

100 hours) - Measurement of solder wetting time using the Meascograph method [Results] The solder wetting time of the product of the present invention was less than Bay compared to that of the conventional product, and the solder wettability was very good.

In addition, in the L experiment, the effect was not significant when the surface area of the outermost layer of the electrode part was 0.511rrL or more in the product of the present invention. - Surface roughness must be 0.5 μm or less.

Advantages of the Invention According to the chip component of the present invention configured as described above, the following effects can be obtained.

(1) An electrode whose surface has been heat-treated and smoothed is smoother than one with only a plating film, so one surface is oxidized.

The attachment of foreign matter and the adsorption of gases are reduced, and the reliability of soldering can be ensured even for long-term use.

Teeth) Since the electrode surface is smooth, when this chip component is mounted on a printed circuit board, it slides easily when it comes into contact with other objects.
Good implementation efficiency.

(3) Since the surface area is smaller than that of matte and mock, there is less adsorption of gases during storage, there are no bubbles from the solder when soldering, and there are no pinholes in the solder finish.
Not only is it beautiful, but it also improves the quality of electronic circuits.

(4) Since the electrode surface is smooth, slippage is improved in the process of manufacturing taping and magazine assemblies, improving flexibility and flexibility, and reducing impact on single parts, improving reliability.

[Brief explanation of drawings]

Figure 14 is a perspective view of a square plate chip resistor which is an example of the present invention; Figure 2 is a new view taken along line 0A-B in Figure 11;
Figure 3 is a characteristic diagram of the measured surface thickness of the same chip resistor, Figure 4 is an analytical diagram of a conventional square plate chip resistor,
FIG. 6 is a characteristic diagram obtained by measuring the '11 thickness of the electrode surface of the same chip resistor. 1...Glass wave, 1 film, 2...Alumina-based isolation substrate, 3...Resistor, 4...Silver-based electrode film-6...・Nickel coating, 7...Solder or Tsuji tin film smoothed by heat treatment. Name of agent: Patent attorney Shigetaka Awano and one other person Figure 2! - Glass liquid 7" and 2" - Alumina display ball Nanazaka 3 - Tun resistance figure

Claims (1)

[Claims] A low melting point metal film is provided as the outermost electrode film of the electrode part, and the base of the low melting point metal film of the electrode part is made of a metal material that has a higher melting point than this low melting point metal film and has good affinity with this low melting point metal film. The surface roughness of the outermost electrode film of the electrode part is 0 to 0.
A chip component having a structure covered with a remelted metal film having a thickness of 0.5 μm.